Semiconductor devices are widely used in different fields as costs and physical dimensions reduce with advancing technologies. Structures of semiconductor devices become more and more complicated because transistor density per unit area increases. Multilevel of conductive pattern features are also adopted to improve performance of semiconductor devices.
Dielectric material is adopted as a structure in semiconductor devices to isolate transistors in different regions. Dielectric material is also utilized to separate conductive patterns located in different levels. As the geometry shrinks, a multi-step method is used to grow the dielectric material in a multi-layer manner. However, the interface between each layer is a weak point of the dielectric material.